<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1 {
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*单独某一个方向添加外边距*/
            margin-left: 100px;
            margin-top: 50px;
            margin-bottom: 50px;
            margin-right: 100px;
            /*四个方向赋值*/
            margin: 50px;
            /*上下50 左右100*/
            margin: 50px 100px;
            /*上右下左顺时针赋值*/
            margin: 10px 20px 30px 40px;
        }
        #d2{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*外边距塌陷: 兄弟元素上下相邻时,彼此添加外边距,取最大值*/
            margin-top: 50px;
        }
        #s1{
            margin-right: 50px;
            margin-bottom: 100px;
        }
        #s2{
            margin-left: 30px;/*左右相邻彼此添加外边距,两者相加*/
        }
        #big{
            width: 200px;height: 200px;background-color: green;
            overflow: hidden;/*解决外边距塌陷导致的粘连问题*/
        }
        #big>div{
            width: 50px;height: 50px;background-color: red;
            margin-left: 50px;
            /*外边距塌陷:父子元素上边缘重叠时,给元素添加外边距,取最大值*/
            margin-top: 50px;
        }
    </style>
</head>
<body>
<div id="big">
    <div></div>
</div>
<span id="s1">span1</span><span id="s2">span2</span>
<div id="d1">div1</div>
<div id="d2">div2</div>
</body>
</html>